Guard for power operated machines



April 16,` 1935. A. LAUKHUFF 1,998,245

GUARD FOR POWER OPERATED MACHINES Filed May 4, 1933 2 Sheets-Sheet 1INVENTOR.

April 16, 1935. A. LAUKHUFF ,1,998,245

I mmm)v FOR PwER OPERATE'D MACHINES Filed May 4, 1953 2 sheets-sheet 2L. v f

@1% MMU-b Ml ATTORNEY;

Patented Apr. 16, 1935 GUARD" Foe POWER. oPuRAritnMACHINEs AlfredLaukhuff,"Milwaukee',- Wis., Yasitigi'ior to; Alfa Machine Company,Milwaukee, rWis.,l a r corporation 'of Wisconsin Application nay 41,y193s;Y serial N I invention'relates to guardsforfm'achines having poweroperated parts liable 'to inflict serious injury to the'operators'thereof. in the event members ofthe operators body are allowed to remaininthe path of movement of the power driven parts when the latter'areactuated The invention is shown as applied to a power driven cuttingmachine but, of course,fis applicable with equal advantage to powerdriven presses or othery types o f machines.

YOnefof the objects of the presenty invention is to provide a guardwhich sweeps from the field of vaction of the power driven partstheopera-V tors hands orA other Amembers of his body, when the power drivenparts are actuated and .pre sents an effective barrieror guardvthroughout the operation of. the power driven partsr'The action of theguardis so timed that it exerts its sweepingaction and is placed inguarding Aor operativepositi'on at Ythe moment of or just prior toactuation of the knife or other power driven part.

Another object. is to 'provide a guard of' this character and'which issimple and durablein construction, compactly V'and closely organized,

" reliable and eiicient in operation and .easy and comparativelylinexpensive to `Inanufac ture and install.

Other objects and advantages 'reside certain novel features of theconstruction, arrangement and combination of partsr which will behereinafter more fully describedl and particularly pointed out in theappended claims, reference being had to the accompanyingdrawings'gforming' 'a part of this specication, and in which:W f'

Figure 1 is a perspective view showing'a guard embodying the presentinvention applied to'` ar power actuated cutter; l

Figure 2 is a fragmentary view'in vertical sectiontaken in the plane ofline 2-2 of Figure 1; Figure 3 is a fragmentary View of themachine shownin Figures l and 2 andlillustrating 'the same in front elevation; and fFigure 4 is a view similar to Figure 2 but showing a slightmodification' in the operating` link` .through linkage designatedgenerally' at 4 and shown in dotted lines in Figure '3, therebeing aclutch interposed between the power source and the movable knife,N whichclutch maybe thrown in and out of engagement by 'actuation of'its clutchcontrol' pjin 6. The cutting machine shown is of the type disclosed andclaimed in my Patent No. 1,565,654, granted December 15,

192.5, ,and the clutch Vreferred to is of the type disclosed' my PatentFebruary 5, 1929. I i r Y The clutchoperating p' is shifted to causethefclutc'h to [be engaged yby means of a foot pedal I fixed on a shaftllsupported for rotation in` bars' I3 provided therefor on the frame I,`A crank arm I4 is fixed to the shaft' II and connects by means of aflinkor Vconnecting rod I5 'withfa lever "I6 mounted for rotation" on a shaft`I1'al`so,' rnounted'on the frame I. The lever I6 isof the bell cranktype and has an arm I8 pivotally y connected to'one end of la' thrustbar I9. The bar I 9 is notched as at 20 and is designatedto coact'withltheclutch control pin'6 to actuate thisjpinand throw inthe clutch whentheV foot Apedal luis depressed.` A spring '2I returns the foot-pedalvto its normal position in which the thrust bar I 3 is lowered and theclutch is disengaged; 'j

An enclosure designatedgenerally at 2 5 is pro-l videdjfor the movableknife 3 and its operating partsV and consists of transverse angles 26supported upon the end structures 21 of the enclosure. Theend'structures 2'IA arefsupported upon and extend upwardlyfromthe table2a of the cutting machine.V A top plate 29 is fixed to these anglesy25.` jAstationaryiguard 3D is secured to and depends fromV one'of theangles whereas a swingable .guardl Vis hinged or vpivotallysupeV portedas at 32 onthe'other; A second swingable guardlmeinber 33jis` providedand -is pivotally mounted yas at 34 on bracketlugs 35 secured to theframe of the machine. Asshown in the dravungs,` the` guard member 43Ijjconsist's of a marginal` metal `frame, 36 to which a sheet oftransparentjmaterial designated at 3l is fastened.

V The guard memberv 331 may consist of a metal plate carried'by an anglebar 38.V

' Linkage is provided between the* guard mem; bersi'3I and 33 toconstrain them to corresponding movement, that is, to movesimultaneously to guarding 'or operative position and'also to movesimultaneously rto finoperative lposition. This linkage consists of.anarr'n' 40 secured to the'guard memberi33 and pivotally at its outerend lto vone ed of.` anni; 41; the other end of the iinkbeing pivoted toa bracket' lug 42 fastenedto the frame o f'the'guard membelji. Whenthefoot pedal I Il isjdepressed thelever Varm I8 swingsto raise the thrustbar I9`and throw in 'the clutchand the present invention .proposes to.utilize lthis motion of the 'lever'a'r'm I8 to swing the guard members3I and;" 33 lt o closed position` before the shoulder 2lir of the'thrustbar engages the clutch operatingpin li'. For this purpose one end of aconnectingrod' V5Il`iis pivoted-.to the outer endof the lever arm I8vadtlijpipvte E'ii'dfifthis con; necting rod is' pivotally connected "to'on'earm'of the bell crank lever 5I fulcrumed on the frame of themachine. The other arm of this lever connects by means of a connectingrod or link 52 with the bracket 42 onA the guard member 3l. With thisarrangementwhen the pedalA I .is delpressed the swinging movement of thelever arm I8 is transmitted through the connecting rod 50, bell cranklever and connecting rodl 52 to the guard 3l thereby swinging'the-guard3| 'to the left, as viewed in Figure 2 and as indicated by the dottedarrow. This motionof the guard 3l, is transmitted to the guard 33through the link 4I and arm 40 so that the guard 33 is raised or swungupwardly in the direction indicated by the dotted arrow. The guard 3l inswinging in the manner described willeectively sweep out of the path ofmovement "of the'knife the hand of the operator and will prevent'theoperator from inserting his hand into the ,field of 'action of theknife. This action of the guard occurs 'every time the pedal isdepressed and the guard remains in guarding position as long as thev`pedal is Vheld depressed.

In the embodiment of the invention shown in Figure 4, a slightly'different linkage is employed between the guards in 'that a crank arm50` is X'ed to the guard 33 and is' 'connected by'a link 5| to a'bracketlug or' arm '52 scuredto the guard 3l. The outer end of the'crankarm 5U' is provided with a crank pin 5 4 fitted in a slot 55 providedinaconnectingrod 56.' Aspring 51 has one end connected to' the'crankpin54 and has its other end'connected to a cross pin 58 secured to the bar56 whereby the spring 51 yieldably holds the pin 54 against one endofthe slot 55. The connecting rod 56y is suitably'connected up with the.lever I8. With this arrangement, the mechanism can be designed to havethe guard 3| swing to full guarding position'befo're the shoulderV 20engages the clutch pinB.l Asv'the foot pedal is further depressed theclutchis thrown into engagement and this further motion ismade possibleby the provision of the vlost motion connection constituted by the crankpin 54 and the slot 55. It will be understood that upon such furthermotion of the foot' p'edaltheba'r' 56 continues to move and itshiftsrelative tothe crank pin 54, the spring 51 yielding to permit of.'this relative movement. i v V While I have shown and describedtypicalembodiments of theinvention, itis' to be understood that thestructures shown have' been selected merely for the purposes ofVillustration and that various changes in the size, shape andarrangement of the parts may be made without departing from the spiritof the invention or the scope of the subjoinedclaims.

The invention claimedis: l. In a machine having a clutch rcontrollingits operation and afoot pedal for engaging `and disengaging the clutch,a. shiftable guard. onthe machine effective to enclose dangerous parts,and

means 'actuatedfrom the 'foot' pedal for shifting saidguard to enclosingposition priorV .to the engagement of the clutch whereby said clutch isprevented from engaging if said guard "is not* in enclosing position.

2. In a machine having 'a clutch controlling its operation and a.control Idevice for engaging and disengaging the clutch, ashiftableenclosing guard on the machineand means actuated from saidcontrol device for kshifting theguard to' enclosing position uponmanipulation of said control device prior to the vtime itengages saidclutch.

3. In a cutter having a movable knife, a power drive for said knife, aclutch in said power drive and a control device for engaging anddisengaging said clutch, a partial enclosure for said knife, a pair ofseparately hinged guard members effective to complete said enclosure,linkage interconnecting said member to constrain them to correspondingmovement and means actuated by said control device for shifting saidguard members to a position completing said enclosure when said controldevice is 'operated to engage said clutch.

4. In a cutterv having a movable knife, a power drivefor said knife, 'aclutch in said power drive and a control device for engaging anddisengaging said clutch, an enclosure for said knife including ashiftable'guardmember acting when in one position to provide for accessto the material being cut while effectinga guard 'for the knife andoperating when shifting to sweep objects away from thepath of the knifeand to providea barrier between the exteriorV of lthe enclosure and thepath of the knife, and means actuated by said control device forshifting said guard member when said control' device is operatedtopengage the clutch and prior to the actuation of the knife. 5.' In amachine of the character described having an operating part, a vpowerdrive for said part, a clutchin said power drive and a control deviceforvengaging and disengaging said clutch, a shiftable guard for saidoperating part, said guard acting in one position to provide for accessto said operating part and acting in another position to providea'barrier preventing access to said part, and means for shifting theguard to the position in which it acts as a barrier when the controldevice is operated to engage the clutch and prior to actual engagementof the clutch.

6. In a machine having a clutch controlling its operation, a shiftableguard on said machine, a foot pedal, motion transmission mechanismbetweensaid foot pedal and said guardand a lost motion connectionbetween the motion transmission mechanism and the clutch whereby whenthe foot pedal is depressed the guard is first moved to positionpreventing access to a part to be guarded and the clutch is thereafteroperated.

'7. In a machine having power actuated parts for operating upon thework, an enclosure for said parts', certain portions of saidV enclosurebeing swingable, and means for swinging said portions from'enclosureaccess position to enclosing position just prior to actuation of saidparts.

8. In a machine having power actuated parts for voperating upon thework, an enclosure for said parts, an entrance for said enclosurecomprising pivotally mounted door-like members, linkage interconnectingsaid members to constrain them to move ysimultaneously to open or closedposition, a power drive for said parts, a device for throwing said powerdrive into operation and means 'connecting vsaid device with one of said"members

